Annulus antennalis: the ring sclerite of the head into which the basal segment of the antennae is inserted; = antennal sclerite.
"Explanation of Terms Used in Entomology" by John. B. Smith
Post-anal sclerite modified as a long, many-jointed feeler.
"Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 3" by Various
S^8, Sclerite between 7th and 8th sterna.
"Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 4" by Various